M3 DISA Valve Issues Causing Multiple Engine Problems

Hey there! M3 owner! I had nearly identical symptoms on my 2007 BMW 335i last year, rough idle, power loss, and CEL. The DISA valve was indeed the culprit. Initially thought it was something minor, but turned out the complete DISA unit needed replacement. The symptoms you're describing match perfectly with what I experienced. Once my DISA valve started failing, the engine performance went downhill pretty quickly. It's not something you want to ignore as it can affect the engine's overall health if left unchecked. Had the work done and can tell you it's a significant repair that requires proper diagnostic equipment and expertise. The mechanic had to remove the intake manifold to access and replace the DISA unit. Took about 4-5 hours total. This isn't a job for an inexperienced shop, you'll want someone who specifically knows BMW engines, particularly the M series. After the repair, the difference was night and day, smooth idle, proper power delivery, and no more check engine light. Hope this helps with your decision!

Thanks for sharing your experience! The symptoms definitely sound similar to what I'm dealing with. Really helpful to hear from someone who's been through it. Would you mind telling me what you ended up paying for the whole repair? Also curious if you've had any other DISA-related issues pop up since getting it fixed?

Hey again! Happy to update you! After getting the repair done at my trusted BMW specialist, I can confirm it was definitely the DISA valve causing all those issues. Total bill came to 280 € for the complete DISA unit replacement, and honestly, it was money well spent. The best part? Haven't had a single DISA-related problem since the fix, my 335i is running like a dream now. The rough idle completely disappeared, power delivery is smooth again, and that annoying check engine light hasn't come back. Such a relief! I know that initial price tag might seem steep, but considering how crucial the DISA valve is for proper engine performance, it's worth getting it done right. Plus, when you think about potential damage to the engine if left unfixed, it's actually quite reasonable. If you're still shopping around for prices, that's about what you should expect to pay for a quality fix. Just make sure whoever does the work knows their BMWs, it makes all the difference. Let me know if you need any other info about the repair. Always happy to help a fellow BMW owner!

Thanks for all the detailed info! After your advice, I bit the bullet and took my M3 to a specialist mechanic. You were spot on about everything, it was indeed the DISA valve causing all those issues. The mechanic was super professional and walked me through the whole process. Found a few other minor issues while they were in there, but nothing major thankfully. Total repair time was about 4 hours, and the final cost was pretty close to what you mentioned. Got the car back yesterday and what a difference! The engine's running smooth as silk now, no more rough idle or power loss. That annoying check engine light is finally gone too. Feels like I've got a new car! Really appreciate you taking the time to share your experience. Helped me make the right call instead of putting it off and potentially causing more damage. Guess sometimes you just have to trust the experts and get it done properly!